WO2016051900A1

WO2016051900A1 - Method for producing 2, 3, 3,3-tetrafluoropropene

Info

Publication number: WO2016051900A1
Application number: PCT/JP2015/069502
Authority: WO
Inventors: 勇博茶木; 大輔加留部
Original assignee: ダイキン工業株式会社
Priority date: 2014-09-30
Filing date: 2015-07-07
Publication date: 2016-04-07
Also published as: JP6583360B2; US20170233315A1; KR20170056691A; JP2016069370A; EP3202755A4; EP3202755A1; CN111960915A; EP3202755B1; JP6300761B2; CN107074695A; JP2017190349A; KR101919265B1; US9975824B2

Abstract

Provided is a method with which a recycling process is established using substantially one reaction step, and 2,3,3,3-tetrafluoropropene (HFO-1234yf) can be efficiently produced. In the present invention, a method for producing 2, 3, 3, 3-tetrafluoropropene (HFO-1234yf) includes a step for reacting a fluorinating agent and at least one type of chlorine-containing starting compound selected from the group consisting of chlorine-containing alkanes represented by general formula (1) CX₂YCHClCH₂Z (where X, Y, and Z are each independently H, F, or Cl) and chlorine-containing alkenes represented by general formula (2) CH₂YCCl=CZ₂ (where X, Y and Z are each independently H, F, or Cl). The molar ratio of the chlorine-containing starting compound, represented by general formula (1) or (2), newly fed to a reactor inlet to the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) of the components at a reactor outlet is less than 1.2.

Description

Method for producing 2,3,3,3-tetrafluoropropene

The present invention relates to a method for producing 2,3,3,3-tetrafluoropropene.

General formula: CF ₃ (CX ₂ ) _n CF═CH ₂ , General formula: CF ₃ (CX ₂ ) _n CH═CHF, etc. (wherein X is H or F, and n is an integer of 0 or more. ) Is a compound useful for various functional materials, solvents, refrigerants, foaming agents, etc., functional polymer monomers and raw materials thereof, such as ethylene-tetrafluoroethylene. It is used as a monomer for modifying copolymers. In particular, among the above-mentioned fluoroolefins, 2,3,3,3-tetrafluoropropene (HFO-1234yf) represented by CF ₃ CF═CH ₂ has recently been promising as a refrigerant compound with a low global warming potential. Is being viewed.

As a method for producing HFO-1234yf, a method in which halopropane or halopropene is used as a raw material and fluorinated with hydrogen fluoride (HF) is known. For example, when fluorinated in the gas phase using 1,1,1,2,3-pentachloropropane (HCC-240db) as a raw material, the reaction proceeds by the following route. (Patent Document 1)
CCl ₃ CHClCH ₂ Cl + 3HF → CF ₃ CCl = CH ₂ + 4HCl (1)
CF ₃ CCl = CH ₂ + HF → CF ₃ CFClCH ₃ (2)
CF ₃ CFClCH ₃ → CF ₃ CF = CH ₂ + HCl (3)
Or without going through the reaction step of the above chemical reaction formula (2),
CCl ₃ CHClCH ₂ Cl + 3HF → CF ₃ CCl = CH ₂ + 4HCl (1)
CF ₃ CCl = CH ₂ + HF → CF ₃ CF = CH ₂ + HCl (4)
There is also a method. (Patent Document 2)

As another method for producing HFO-1234yf, instead of HCC-240db, 1,1,2,3-tetrachloropropene (HCO-1230xa) is used as a raw material. It is also possible to produce HFO-1234yf using a similar process. (Patent Document 3)

In any of the above cases, the conventionally proposed methods require two or more reaction steps to produce the target product, HFO-1234yf, from the raw material halopropane or halopropene. On the other hand, Patent Document 4 and Patent Document 5 have found that HFO-1234yf can be produced to a small extent by fluorinating the raw material halopropane or halopropene in one reactor. We have also proposed a process for recycling 2-chloro-3,3,3-trifluoro-propene (HCFO-1233xf), the main product of the reaction that can be an intermediate of HFO-1234yf. However, under the conditions of the examples shown in these prior documents, when the actual recycling process is performed, unreacted HCFO-1233xf and HF continuously increase in the system, and the steady process is performed. Is impossible. Therefore, in order to solve this, a process of extracting unreacted HCFO-1233xf, HF, etc. out of the system, a storage device, a reaction process in a separate process, etc. are required, which increases equipment costs and manufacturing costs. Connected.

JP 2009-227675 A Special Table 2013-537167 WO2012 / 099776 US61 / 511,663 Publication Special Table 2014-511349

The present invention has been made in view of the above-described conventional state of the art, and the main object thereof is general formula (1):
CX ₂ YCHClCH ₂ Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX ₂ YCCl = CZ ₂
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
In the method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) using at least one chlorine-containing compound selected from the group consisting of chlorine-containing alkenes represented by the following: The aim is to provide a method for efficiently producing HFO-1234yf by an economically advantageous method by establishing a recycling process using a reaction process, reducing energy costs, equipment costs, and the like.

The present inventor has intensively studied to achieve the above-mentioned purpose. As a result, in the method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) using the above specified chlorine-containing compound as a raw material, it replaces the conventional production process using substantially two or more reaction steps. In the case of adopting a recycling process consisting essentially of one reaction step and necessary separation and purification steps by controlling the ratio of the chlorine-containing compound that is the raw material and the fluorinating agent, the equipment is compared with conventional equipment. It has been found that costs can be reduced and energy costs associated with heating and cooling can be reduced. The present invention has been completed as a result of further studies based on these findings.

That is, the present invention provides the following method for producing HFO-1234yf.

Item 1. A method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf), which is represented by the general formula (1):
CX ₂ YCHClCH ₂ Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX ₂ YCCl = CZ ₂
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
A reaction step of at least one chlorine-containing raw material compound selected from the group consisting of chlorine-containing alkenes and a fluorinating agent, and 2-chloro-3,3,3-trifluoropropene as a reactor outlet component The molar ratio of the chlorine-containing raw material compound newly supplied to the reactor inlet with respect to the molar amount of (HCFO-1233xf) is less than 1.2.
Production method.

Item 2. Item 2. The production method according to Item 1, wherein the molar ratio of the fluorinating agent supplied to the reactor exceeds 50 with respect to the molar amount of the chlorine-containing raw material compound newly supplied to the reactor inlet.

Item 3. Item 3. The production method according to Item 1 or 2, wherein the pressure in the reaction step is 0 to 0.3 MPa.

Item 4. Item 4. The production method according to any one of Items 1 to 3, wherein a molar ratio of the chlorine-containing raw material compound newly supplied to the reactor inlet is 0.3 or less with respect to a molar amount of HCFO-1233xf as the reactor outlet component.

Item 5. Item 5. The production method according to any one of Items 1 to 4, comprising circulating at least a part of the product of the reaction step, the unreacted chlorine-containing raw material compound, and the fluorinating agent at the reactor outlet to the reaction step. .

Item 6. HFO-1234yf and / or HCl is separated from the product of the reaction step at the reactor outlet, and at least a part of the remaining product, unreacted chlorine-containing raw material compound and fluorinating agent is circulated to the reaction step. Item 6. The production method according to any one of Items 1 to 5, further comprising:

Item 7. Item 7. The production method according to any one of Items 1 to 6, wherein at least one of the chlorine-containing raw material compounds represented by the general formula (1) is 1,1,1,2,3-pentachloropropane (HCC-240db). .

Item 8. Item 7. The production method according to any one of Items 1 to 6, wherein at least one of the chlorine-containing raw material compounds represented by the general formula (2) is 1,1,2,3-tetrachloropropene (HCO-1230xa).

Item 9. Item 9. The production method according to any one of Items 1 to 8, wherein the concentration of HCl contained in the reactor outlet component in the reaction step is 10 mol% or less with respect to the total amount of the reactor outlet component.

Item 10. Item 10. The production method according to any one of Items 1 to 9, wherein the fluorinating agent is anhydrous hydrogen fluoride.

Item 11. Item 11. The production method according to any one of Items 1 to 10, wherein the catalyst used in the reaction step is chromium oxide and / or fluorinated chromium oxide.

Item 12. Item 12. The production method according to any one of Items 1 to 11, wherein the concentration of HCl contained in the component circulating in the reaction step is 5 mol% or less with respect to the circulating chlorine-containing compound.

Item 13. Item 13. The production method according to any one of Items 1 to 12, wherein O ₂ and / or Cl ₂ are entrained in the reaction step.

According to the method of the present invention, the general formula (1):
CX ₂ YCHClCH ₂ Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX ₂ YCCl = CZ ₂
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
From at least one chlorine-containing raw material compound selected from the group consisting of chlorine-containing alkenes represented by , 3-tetrafluoropropene (HFO-1234yf) can be obtained.

FIG. 3 is a reaction process flow diagram in Examples 1 and 2 and Comparative Examples 1 to 3.

Here, the separation step in the figure means all steps including the various separation methods shown above, and the implementation conditions can be selected as appropriate.

Hereinafter, the present invention will be specifically described. The main propane and propene related to the present invention are defined as shown in Table 1. However, in some tables, the characters before the numbers are omitted.

In the present invention, the general formula (1):
CX ₂ YCHClCH ₂ Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX ₂ YCClCZ ₂
(In the formula, X, Y, and Z are each independent and represent H, F, or Cl.)
HFO-1234yf can be obtained substantially by one reaction step from at least one chlorine-containing raw material compound selected from the group consisting of chlorine-containing alkenes.

The production method of the present invention includes a reaction step in which a specific chlorine-containing raw material compound is reacted with a fluorinating agent to produce HFO-1234yf, an unreacted chlorine-containing raw material compound in the reactor outlet component, a fluorinating agent, and an intermediate. And a step of separating by-products such as HCl and the target HFO-1234yf, a step of purifying HFO-1234yf separated in the separation step, and an unreacted chlorine-containing raw material separated in the separation step A step of recycling and recycling at least a part of the compound, the fluorinating agent and the intermediate to the original reaction step.

This is an embodiment of the production method according to the present invention. For example, a fluorinating agent, a chlorine-containing fluoride that can be an intermediate of HFO-1234yf, a by-product such as HCl, and the like are separated and purified from components in each step. It does not prevent further including a process. Moreover, it does not prevent including the detoxification process which removes a fluorinating agent, HF, HCl, etc. from the component of each process. An essential feature of the present invention is to produce HFO-1234yf using substantially one reaction step. Here, one reaction step means that the reaction pressure and the reaction temperature are substantially the same conditions, and are substantially the same conditions as long as they are within the range of the pressure difference and the temperature difference generated in the process operation. It can be said. For example, the absolute pressure and the absolute temperature are within a range of about ± 10 to 20%.

In the embodiment of the present invention, the HCl concentration in the component to be recycled and reused is preferably 5 mol% or less, more preferably 1 mol% or less of the chlorine-containing compound to be recycled and reused.

In the case of circulation, usually, a chlorine-containing raw material compound and a fluorinating agent are newly supplied to the reactor. However, the methods conventionally proposed (for example, implementations shown in Patent Document 4 and Patent Document 5) are used. In the example condition), when the process of actual recycling is performed, unreacted HCFO-1233xf and HF continuously increase in the reaction system, and it is impossible to perform a steady process.

On the other hand, as a result of intensive studies by the present inventors, when carried out under the conditions of the present invention, substantially the same amount of the chlorine-containing raw material compound and / or the generated HCl as substantially the same amount as the generated HFO-1234yf. By supplying the same amount of the fluorinating agent to the above reaction step, steady operation became possible.

According to the method of the present invention having these characteristics, it is possible to efficiently obtain HFO-1234yf by an economically advantageous method while reducing energy costs and equipment costs.

Hereinafter, each step of the present invention will be specifically described.

(1) Reaction process general formula (1):
CX ₂ YCHClCH ₂ Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX ₂ YCCl = CZ ₂
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
The fluorination reaction is carried out by using at least one chlorine-containing raw material compound selected from the group consisting of chlorine-containing alkenes represented by the above as a raw material and reacting it with a fluorinating agent in the presence or absence of a catalyst. . Thereby, HFO-1234yf can be obtained.

As the fluorinating agent, for example, anhydrous hydrogen fluoride, fluorine, trifluoromethane, or the like can be used. In particular, anhydrous hydrogen fluoride is preferable.

At least one chlorine-containing compound selected from the group consisting of a chlorine-containing alkane represented by the general formula (1) and a chlorine-containing alkene represented by the general formula (2) used as a raw material is a known compound that can be easily obtained. is there.

Hereinafter, as a reaction example, a method of performing fluorination by gas phase reaction using anhydrous hydrogen fluoride in the presence of a fluorination catalyst will be specifically described.

As the fluorination catalyst, a known catalyst that is active for the fluorination reaction with hydrogen fluoride can be used. In particular, it is preferable to use a fluorination catalyst containing a chromium atom. HFO-1234yf can be obtained by using such a catalyst and reacting a chlorine-containing compound as a raw material with anhydrous hydrogen fluoride according to the conditions described later.

As the fluorination catalyst containing a chromium atom, chromium halide, chromium oxide or the like can be used. Among these, examples of preferred catalysts include CrCl ₃ , CrF ₃ , Cr ₂ O ₃ , CrO ₂ , CrO _{3 and the} like. As these catalysts, catalysts supported on a carrier can be used. The carrier is not particularly limited, and examples thereof include porous alumina silicate represented by zeolite, aluminum oxide, silicon oxide, activated carbon, titanium oxide, zirconia oxide, zinc oxide, and aluminum fluoride.

In the present invention, it is particularly preferable to use at least one catalyst selected from the group consisting of chromium oxide and fluorinated chromium oxide.

Among these catalysts, for example, chromium oxide is not particularly limited. For example, in the composition formula: CrO _m , it is preferable to use one in which m is in the range of 1 <m <3, and 1 <m It is more preferable to use those in the range of <2. Any shape of the chromium oxide catalyst can be used as long as it is suitable for the reaction such as powder or pellets. The fluorinated chromium oxide can be obtained, for example, by fluorinating the above-described chromium oxide with hydrogen fluoride (HF treatment).

Further, a chromium-based catalyst mainly composed of a chromium compound to which at least one metal element selected from the group consisting of indium, gallium, cobalt, nickel, zinc, aluminum, vanadium and niobium is added is also a chromium oxide catalyst or It can be used as a fluorinated chromium oxide catalyst. As the chromium-based catalyst, either an amorphous chromium-based catalyst or a partly or entirely crystalline chromium-based catalyst can be used.

As for the fluorination reaction, when anhydrous hydrogen fluoride is used as a fluorinating agent, it can be supplied to a reactor together with a chlorine-containing compound as a raw material. Regarding the amount of anhydrous hydrogen fluoride supplied to the reactor, in order to increase the yield of the target substance, HFO-1234yf, to 1 mol of chlorine-containing compound newly supplied to the reactor as a raw material The amount is preferably about 10 mol or more, more preferably more than 50 mol, and still more preferably about 100 mol or more. The amount of anhydrous hydrogen fluoride is preferably within the above range from the viewpoints of selectivity of HFO-1234yf, maintenance of catalytic activity, productivity, and the like. Usually, the amount of anhydrous hydrogen fluoride is preferably about 500 mol or less, more preferably about 400 mol or less, per 1 mol of chlorine-containing compound newly supplied to the reactor as a raw material. Further, the concentration of HCl contained in the reactor outlet component is preferably 10 mol% or less with respect to the total amount of the reactor outlet component.

The concentration of anhydrous hydrogen fluoride supplied to the reactor may be in the above range, but in order to produce HFO-1234yf continuously in one reaction step, that is, the chlorine-containing raw material compound to be newly supplied In order to maintain a balance between the amount of HFO-1234yf produced and the amount of HFO-1234yf produced, the amount of anhydrous hydrogen fluoride supplied along with various reaction conditions such as reaction temperature, reaction pressure, and contact time must be adjusted. Since the optimum amount of anhydrous hydrogen fluoride supplied greatly affects the amount of HCl produced as a by-product, the optimum amount cannot be easily determined. The present inventors have found the optimum condition range through intensive studies.

As an example of a specific embodiment of the present invention, a tubular flow reactor is used, the reactor is filled with a fluorination catalyst, and a chlorine-containing compound and anhydrous hydrogen fluoride used as raw materials are introduced into the reactor. The method of doing can be mentioned.

The reaction temperature is advantageous in that the lower the temperature, the less the decomposition of the raw materials and products, so the lower limit is not particularly limited, preferably 300 ° C. or higher, more preferably 350 ° C. or higher. preferable.

The reaction temperature is preferably about 500 ° C. or less from the viewpoint of maintaining catalytic activity and suppressing by-product formation of isomers. A more preferred reaction temperature is about 350 to 450 ° C.

The pressure during the reaction is not particularly limited, and the reaction can be carried out under reduced pressure, normal pressure or increased pressure. Usually, the reaction can be carried out under a pressure in the vicinity of atmospheric pressure (0.1 MPa), and the reaction can proceed smoothly even under a reduced pressure of less than 0.1 MPa. Furthermore, the reaction can be performed under a pressure that does not liquefy the raw material. However, from the viewpoint of suppressing the decrease in the selectivity of the target HFO-1234yf, suppressing the decrease in catalyst life, etc., the pressure during the reaction is preferably 1 MPa or less, more preferably 0.7 MPa or less, and even more preferably 0.3 MPa or less. carry out.

The contact time is not limited. For example, the ratio of the catalyst filling amount W (g) to the total flow rate F _{0 of the} raw material gas flowing into the reaction system (flow rate at 0 ° C. and 0.1013 MPa: cc / sec): W / F _The contact time represented by ₀ is preferably about 0.5 to 50 g · sec / mL, and more preferably about 1 to 30 g · sec / mL.

The raw material may be supplied to the reactor as it is, or a raw material such as nitrogen, helium, or argon or a gas inert to the catalyst may coexist. The concentration of the inert gas can be about 0 to 80 mol% of the gas component introduced into the reactor.

Further, when a gas phase reaction is carried out in the presence of a catalyst, O ₂ and / or Cl ₂ can be supplied to the reaction apparatus together with the raw materials in order to maintain the catalytic activity for a long period of time. Thereby, the fall of catalyst activity can be suppressed.

(2) Separation step In the present invention, HFO-1234yf produced in the above reaction step is separated from unreacted chlorine-containing raw material compounds, fluorinating agents, intermediates, byproducts such as HCl, and the like. At least a part of the chlorine raw material compound, the fluorinating agent and the intermediate is recycled to the reaction step. This separation step can be selected in any form, and a plurality of different separation steps may be selected. Specifically, this separation step can be distillation, liquid-liquid separation, extractive distillation, or liquid-liquid extraction separation, or a combination thereof. These are merely examples and do not limit the separation step in carrying out the present invention. The steps and separation conditions can be separated into a fraction containing HFO-1234yf and a fraction substantially free of HFO-1234yf. The fraction that does not substantially contain HFO-1234yf is recycled to the reaction process. In this case, in order to prevent HFO-1234yf from being contained substantially in the component to be recycled, the fraction containing HFO-1234yf is substantially the same amount as HFO-1234yf introduced in the separation step. HFO-1234yf is preferably included. Furthermore, as described above, HCl during the reaction reduces the yield of the target product, HFO-1234yf, and in some cases, an increase in unwanted by-products that cannot be an intermediate of the target product, HFO-1234yf. Therefore, the lower the HCl concentration of the component recycled from the separation step to the reaction step, the better, and it is preferably 5 mol% or less, preferably 1 mol% or less with respect to the chlorine-containing raw material compound in the component to be recycled. More preferably. For this purpose, HCl may be contained in the above-mentioned fraction containing HFO-1234yf, and in the HFO-1234yf purification step, the HFO-1234yf fraction which is substantially free of HCl can be finally purified. it can.

The components that do not contain HFO-1234yf separated in this separation step are further subjected to a crude treatment step (separation step) such as distillation, if necessary, so that they can be used in the reaction step. After separating at least one selected from the group consisting of a chlorine raw material compound, an intermediate and a fluorinating agent and a chlorine-containing fluorine compound that cannot be an intermediate of HFO-1234yf, each of them can be used in the reaction process. At least a part of the chlorine-containing raw material compound, the fluorinating agent and the intermediate in the reaction can be recycled to the reaction step and reused.

The fraction containing HFO-1234yf is further subjected to the process of purifying HFO-1234yf, and then unreacted chlorine-containing raw material compounds, fluorinating agents, intermediates, etc. that can be used in the reaction process are separated and circulated. Can be reused.

Here, the intermediate includes a compound produced as a result of a reaction such as chlorine-fluorine substitution, hydrogen fluoride addition, dehydrochlorination, dehydrofluorination, etc. of a chlorine-containing compound used as a raw material. Specifically, depending on the process used and the reaction conditions, 1,1,2,3-tetrachloro-1-fluoropropane (HCFC-241db), 1,1,2-trichloro-1,3-difluoropropane (HCFC-242dc), 2,3,3-trichloro-3-fluoropropene (HCFO-1231xf), 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf), 2-chloro-3,3, Examples thereof include 3-trifluoropropene (HCFO-1233xf) and 1,1,1,2,2-pentafluoropropane (HFC-245cb).

When circulating and reusing the fraction in the separation step, a deoxidation step, a water removal step, a rough purification step such as distillation, etc. can be installed as necessary. The processing conditions for each of these steps can be appropriately set according to the components to be separated.

Examples of specific conditions when hydrogen fluoride (HF) is used as the fluorinating agent in the reaction step will be given for the case where distillation is employed in the separation step.

The condition for separating HFO-1234yf from the component recycled to the reaction step from the reactor outlet component of the reaction step is to separate unreacted chlorine-containing raw material compounds, HF, intermediates, etc. as low-boiling components, and low boiling point As components, HFO-1234yf, hydrogen chloride, and the like can be separated. Since both the chlorine-containing raw material compound and the intermediate in the present invention have a higher boiling point than the target product HFO-1234yf, the high-boiling components separated in this way can be recycled in the reaction process. The component that does not become an intermediate of HFO-1234yf contained in the high boiling point component can be further separated into the separated component by supplying it to the separation step before circulating to the reaction step. Further, for the purpose of suppressing deterioration of the catalyst used in the reaction step, it is preferable to separate and remove components that do not become intermediates of HFO-1234yf from components that are recycled.

A component containing HFO-1234yf, hydrogen chloride, etc. separated as a low boiling point component is further subjected to any purification process such as single or multistage distillation, liquid separation, extraction, extractive distillation, etc. HFO-1234yf can be separated and recovered from the separated components including HFO-1234yf and hydrogen chloride. For example, when performing a distillation operation as a separation means, a component containing HFO-1234yf, hydrogen chloride, etc. separated as a low boiling point component is subjected to a single or multistage distillation step, and the bottom or column of the final distillation column High-purity HFO-1234yf can be recovered from the middle stage, and hydrogen chloride can be recovered from the top of the column and reused for the desired purpose. The other organic component contained in the fraction containing hydrogen chloride is chlorine-containing fluoride and can be used as an intermediate in the fluorination reaction, so it is separated from other components during the process of recovering HFO-1234yf Thus, it can be recycled to the reaction process. Further, when O ₂ is introduced in the fluorination reaction step for the purpose of maintaining the catalyst life, since O ₂ is contained in the fraction containing hydrogen chloride, it can be recycled to the reaction step.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
According to the flow chart shown in FIG. 1, HFO-1234yf was produced by carrying out a fluorination reaction using HCC-240db as a raw material and substantially using one reactor.

The reactor was a Hastelloy reactor, and was charged with 21 g of chromium oxide containing Cr ₂ O ₃ as the main component (chromium hydroxide calcined at 700 ° C or higher for 2 hours or more in air at atmospheric pressure). . As a pretreatment for using the catalyst in the reaction, anhydrous hydrogen fluoride diluted with nitrogen was circulated, and the temperature of the reactor was changed from 200 ° C. to 360 ° C. to carry out the fluorination treatment.

The reactor was heated by an electric furnace, and after reaching a predetermined temperature, the reaction process shown in FIG. 1 was started. O ₂ was introduced from the reactor inlet so as to be 10 mol% with respect to the total organic matter at the reactor inlet.

The operating conditions for the reaction were a pressure of 0.0 MPaG and a temperature of 365 ° C. The composition of components at each stage of the reaction process (F1 to 6 in FIG. 1) was analyzed using a gas chromatograph. The analysis results are shown in Table 2 below.

Example 2
According to the flow chart shown in FIG. 1, HFO-1234yf was produced by carrying out a fluorination reaction using HCC-240db as a raw material and substantially using one reactor.

The reactor was a Hastelloy reactor and was charged with 15 g of chromium oxide containing Cr ₂ O ₃ as the main component (chromium hydroxide calcined at 700 ° C or higher for 2 hours or more in air at atmospheric pressure). . As a pretreatment for using the catalyst in the reaction, anhydrous hydrogen fluoride diluted with nitrogen was circulated, and the temperature of the reactor was changed from 200 ° C. to 380 ° C. to carry out the fluorination treatment.

After the reactor was heated by an electric furnace and reached a predetermined temperature, the reaction process shown in FIG. 1 was started. O ₂ was introduced from the reactor inlet so as to be 10 mol% with respect to the total organic matter at the reactor inlet.

The operating conditions for the reaction were a pressure of 0.12 MPaG and a temperature of 380 ° C. The composition of components at each stage of the reaction process (F1 to 6 in FIG. 1) was analyzed using a gas chromatograph. The analysis results are shown in Table 3 below.

Comparative Examples 1 to 3
Regarding Examples 1-2, 2 and 3 of Patent Document 4, as described in Patent Document 4, a method of continuously circulating the entire amount of HCFO-1233xf and HF out of the reactor outlet components to the reactor was studied. . Table 4 shows the reaction conditions and reactor outlet composition results of Examples 1-1 to 3 in Patent Document 4. A simulation is performed in the case where the flow shown in FIG. 1 is performed so that the molar ratio of W / F ₀ and HF / 240 db is the same as the reaction conditions of Examples 1-2, 2 and 3 of Patent Document 4, and Comparative Examples 1 to It was set to 3. The composition of components at each stage of the reaction process (F1 to 6 in FIG. 1) was analyzed using a gas chromatograph. The results of Comparative Examples 1 to 3 are shown in Tables 5 to 7, respectively.

Table 8 summarizes the reaction conditions of Examples 1-2 and Comparative Examples 1-3, the amount of HFO-1234yf produced, and the yield of HFO-1234yf relative to the supplied HCC-240db.

As shown in Tables 5 to 7, the entire amount of HCFO-1233xf and HF, which are the components at the outlet of the reactor, could not be circulated, and it was necessary to supply a part to another process. The reason is that the flow rate at the inlet and outlet of the reactor cannot be balanced, and it is clear that excess HCFO-1233xf that can be an intermediate of HFO-1234yf and unreacted HF need to be supplied to another process. is there.

Further, as shown in Table 8, when the present invention is used, HFO-1234yf can be produced industrially advantageously in substantially one reaction step.

Claims

A method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf), which is represented by the general formula (1):
CX 2 YCHClCH 2 Z
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
Chlorine-containing alkane represented by the general formula (2):
CX 2 YCCl = CZ 2
(In the formula, X, Y and Z are each independent and represent H, F or Cl.)
A reaction step of at least one chlorine-containing raw material compound selected from the group consisting of chlorine-containing alkenes and a fluorinating agent, and 2-chloro-3,3,3-trifluoropropene as a reactor outlet component The molar ratio of the chlorine-containing raw material compound newly supplied to the reactor inlet with respect to the molar amount of (HCFO-1233xf) is less than 1.2.
Production method.
The production method according to claim 1, wherein a molar ratio of the fluorinating agent supplied to the reactor exceeds 50 with respect to a molar amount of the chlorine-containing raw material compound newly supplied to the reactor inlet.
The production method according to claim 1 or 2, wherein the pressure in the reaction step is 0 to 0.3 MPa.
The production method according to any one of claims 1 to 3, wherein a molar ratio of the chlorine-containing raw material compound newly supplied to the reactor inlet is 0.3 or less with respect to a molar amount of HCFO-1233xf as the reactor outlet component. .
The production according to any one of claims 1 to 4, comprising circulating at least a part of the product of the reaction step, the unreacted chlorine-containing raw material compound, and the fluorinating agent at the reactor outlet to the reaction step. Method.
HFO-1234yf and / or HCl is separated from the product of the reaction step at the outlet of the reactor, and at least a part of the remaining product, unreacted chlorine-containing raw material compound and fluorinating agent is supplied to the reaction step. The production method according to any one of claims 1 to 5, comprising circulating.
7. The chlorine-containing raw material compound represented by the general formula (1), wherein at least one is 1,1,1,2,3-pentachloropropane (HCC-240db). Production method.
The production according to any one of claims 1 to 6, wherein at least one of the chlorine-containing raw material compounds represented by the general formula (2) is 1,1,2,3-tetrachloropropene (HCO-1230xa). Method.
The production method according to any one of claims 1 to 8, wherein the concentration of HCl contained in the reactor outlet component in the reaction step is 10 mol% or less with respect to the total amount of the reactor outlet component.
The production method according to any one of claims 1 to 9, wherein the fluorinating agent is anhydrous hydrogen fluoride.
The production method according to any one of claims 1 to 10, wherein the catalyst used in the reaction step is chromium oxide and / or fluorinated chromium oxide.
The production method according to any one of claims 1 to 11, wherein the concentration of HCl contained in the component circulating in the reaction step is 5 mol% or less with respect to the circulating chlorine-containing compound.
The production method according to any one of claims 1 to 12, wherein O 2 and / or Cl 2 are entrained in the reaction step.